From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755565Ab1DSVE0 (ORCPT ); Tue, 19 Apr 2011 17:04:26 -0400 Received: from kroah.org ([198.145.64.141]:39373 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755505Ab1DSVEW (ORCPT ); Tue, 19 Apr 2011 17:04:22 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Apr 19 14:03:23 2011 Message-Id: <20110419210323.340636093@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Tue, 19 Apr 2011 14:02:26 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Artem Bityutskiy Subject: [10/26] UBIFS: fix oops when R/O file-system is fsynced In-Reply-To: <20110419210333.GA17417@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Artem Bityutskiy commit 78530bf7f2559b317c04991b52217c1608d5a58d upstream. This patch fixes severe UBIFS bug: UBIFS oopses when we 'fsync()' an file on R/O-mounter file-system. We (the UBIFS authors) incorrectly thought that VFS would not propagate 'fsync()' down to the file-system if it is read-only, but this is not the case. It is easy to exploit this bug using the following simple perl script: use strict; use File::Sync qw(fsync sync); die "File path is not specified" if not defined $ARGV[0]; my $path = $ARGV[0]; open FILE, "<", "$path" or die "Cannot open $path: $!"; fsync(\*FILE) or die "cannot fsync $path: $!"; close FILE or die "Cannot close $path: $!"; Thanks to Reuben Dowle for reporting about this issue. Signed-off-by: Artem Bityutskiy Reported-by: Reuben Dowle Signed-off-by: Greg Kroah-Hartman --- fs/ubifs/file.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1311,6 +1311,9 @@ int ubifs_fsync(struct file *file, struc dbg_gen("syncing inode %lu", inode->i_ino); + if (inode->i_sb->s_flags & MS_RDONLY) + return 0; + /* * VFS has already synchronized dirty pages for this inode. Synchronize * the inode unless this is a 'datasync()' call.